Well here's some pics from this weekend:
steel-wool-ed the acrylic sheet:
the acrylic was blue. I think if you painted it it woudl be tough to get the transparency even.
The paint I ended up liking best for the hardboard were Krylon Bali Sea. If I wanted it darker Valspar Night Tide was very pretty as well. Both had significant green tones to it.
I think if you painted it pure blue and had a blue acrylic in front it would be a little too blue but that's just me